Underground, submarine and superconducting cables: Geopolitics and regulation

Germany's U-turn on burying lines, and anchors that cut links

Cables win permits more easily than pylons because they are out of sight, but they cost several times more, and Germany is now legislating to switch new DC lines back to overhead. At sea, anchor damage in the Baltic has turned cable security into a defence and legal issue.

Tailwinds

Germany has favoured underground cables for new long-distance DC lines since 2015, so SuedLink was replanned underground after local opposition to pylons; it is due in service by the end of 2028.¹¹¹⁶

Viking Link (£1.7 billion, National Grid and Energinet) began commercial operation on 29 December 2023, linking the GB and Danish markets.⁴⁵

Adopted 21 February 2025 for power and data cables: risk assessments, sea-basin surveillance, reserve repair vessels and spare parts, and sanctions on saboteurs including 'shadow fleet' ships. A second EUR 40 million call for repair equipment (telecom cables) opened in June 2026.¹²²⁸

National Grid's 2025 HVDC framework reserves capacity with six cable makers and four converter suppliers.²⁰²³

Headwinds

A draft law agreed in April 2026 makes overhead lines the default for new high-voltage lines, including new DC lines such as DC42, with some exceptions; the Federal Network Agency estimates about EUR 35 billion saved by 2045. At a Bundestag hearing on 22 June 2026 grid operators warned that redesigns could delay projects by two years or more.¹¹²⁶

Estlink 2 (Finland to Estonia) lost 650 MW for about six months after the tanker Eagle S dragged its anchor on 25 December 2024. A Helsinki court dismissed the charges in October 2025 for lack of jurisdiction; another ship was detained after a Helsinki-Tallinn telecom cable was damaged on 31 December 2025.^13142529

Cable procurement takes two to three years and DC cables more than five years; real cable prices have nearly doubled since 2019.¹⁰¹⁸

In GB, building, deep cultivation and tree planting are restricted over the cable easement, so rights of way must be negotiated with landowners.³

The policy balance is between public acceptance (cables) and cost to bill payers (overhead lines), and Germany's 2026 bill swings it towards cost. At sea, one anchor can cut hundreds of megawatts of cross-border supply for months, and the Eagle S ruling showed how hard such damage is to prosecute outside territorial waters.

Sources

1. Undergrounding high voltage electricity transmission lines: the technical issues (Issue 4) National Grid, 2015
2. National Grid announces commercial operations of Viking Link National Grid, 2023
3. Laying of world record power cable between the UK and Denmark now complete National Grid Ventures, 2023
4. Rising component prices and supply chain pressures are hindering the development of transmission grid infrastructure IEA, 2025
5. Germany plans switch from underground to overhead power lines to cut costs: report Clean Energy Wire, 2026
6. Drones, spare parts and sanctions: EU unveils action plan for submarine cable security Eunews, 2025
7. Smooth repair work brings EstLink 2 connection back to market already on Friday Elering, 2025
8. Estlink 2 electricity transmission link returns to commercial use Fingrid, 2025
9. Germany starts construction on two more stages for 4 GW SuedLink HVDC cable S&P Global Commodity Insights, 2025
10. Building the Future Transmission Grid: executive summary IEA, 2025
11. National Grid Framework Agreement Jan De Nul, 2025
12. National Grid awards HVDC supply chain framework contracts National Grid, 2025
13. Helsinki Court Dismisses Charges in Case of Cable Damage by Tanker Eagle S The Maritime Executive, 2025
14. Bundesbedarfsplangesetz: Anhörung im Ausschuss für Wirtschaft und Energie (Drucksache 21/6128) Deutscher Bundestag, 2026
15. CEF Digital: second call for proposals to increase Europe's submarine cable repair capacities launched European Health and Digital Executive Agency (HaDEA), European Commission, 2026
16. Finland seizes ship sailing from Russia after suspected cable sabotage Al Jazeera, 2025